Flowable, aqueous pearly luster dispersion containing behenic acid as pearlescent component and lauryl ether sulfate as dispersant
This invention relates to a flowable or pumpable, aqueous pearly luster dispersion comprising 5-30% of pearlescent components.
In order to give surfactant formulations a better appearance and thus also a higher commercial value, pearly luster dispersions are often incorporated. Examples thereof include liquid washing and cleaning products (e.g. floor cleaners and dishwashing compositions) and liquid cosmetics preparations (e.g. body care and body cleansing products, shampoos, bath products, etc.). Pearly luster dispersions give the formulations a silky or mother-of-pearl-like appearance. The effect is produced by light scattering at the dispersed, mostly leaf-shaped crystals of the pearlescent components.
Pearly luster dispersions according to the prior art mainly comprise at least one pearlescent compound, at least one dispersant and water. Examples of pearlescent compounds are fatty acid monoalkanolamides, fatty acid dialkanolamides, monoesters or diesters of ethylene glycol or mixtures thereof, propylene glycol or its oligomers, mono- or diesters of alkylene glycols with fatty acids, fatty acids and their metal salts, monoesters or polyesters of glycerol with carboxylic acids and keto sulfones of various types.
Pearly luster concentrates based on the aforementioned pearlescents are known, for example, from DE-A-16 69 152, JP-56/71021 (Chem. Abstr. 95/156360), DE-A-34 11 328 and DE-A-35 19 081.
The concentrates known from these publications include fatty acid monoalkanolamides or fatty acid dialkanolamides as part of the pearlescent substances. However, alkanolamides and their derivatives are suspected of contributing to the formation of nitrosamines. It is therefore desired to formulate cosmetic preparations without such alkanolamides and alkanolamide derivatives.
Omitting the fatty acid alkanolamides from the known pearly luster concentrates does, however, lead to a marked reduction in the pearlescent properties. DE-37 24 547 has thus already proposed the use of essentially linear, saturated fatty acids, including inter alia behenic acid, as pearlescent substance.
EP-0 449 904 discloses that markedly higher concentrations of pearlescent substances must be used in order to obtain a satisfactory pearly luster in the final product. It also describes how pearly luster products based on fatty acids, their salts and their esters as the pearlescent component have only low thermal stability and become partially or completely dissolved at the usual use concentrations in surfactant formulations during storage. These disadvantages have meant that such systems have not become established on the market.
The object was therefore to develop a pearly luster product which does without fatty acid alkanolamides or fatty acid esters, has good stability on storage, and brings about a pearlescence effect which corresponds to the prior art.